Production of solvents



PRODUCTION OF SOLVENTS Filed Aug. 14 1940 5w fue @muc/Mz: CAA/1455szw/PFW@ CHA M55? Pf6/ouf l l www! wb Patented May 25, 1943 PRODUCTIONOF SOLVENTS Jacquelin E. Harvey, Jr., Atlanta, Ga., assigner of one-halfto Southern Wood Preserving Company, East Point, Ga., a corporation ofGeorgia Application August 14, 1940, Serial No. 352,671 1 claim. (o1.19e- 53) The present invention relates to the production of valuableliquids from tars of aromatic content and fractions thereof, crudeand/or refined.

An object of the present invention is the sube jection of tars ofaromatic content and fractions thereof, crude and/or refined, to theaction of hydrogen in step-wise manner, whereby to provide solvents ofincreased solvency, said solvents being characterized when compared toan intermediate sta'rting material of the process, by a fractionalincrement in the low boiling range in excess of fractional increment inthe higher boiling range.

A further object of the present invention is the production of refinedsolvents of lowered corrosivity, the characteristics of which are, amongother things, dependent upon hydrogen supply, as hereafter explained.

Starting materials of the present invention include tars and fractionsthereof derived from coal, petroleum and gas or gases of carbon content,as for instance coke oven tar, water gas tar, gas house tar, and tars ofaromatic content in general; as for instance tars of aromatic contentderived from coal and fractions thereof; tars produced by crackinghydrocarbons; tars resulting from the' action of hydrogen onhydrocarbons; tars resulting from polymerization; high boiling extractsof carbonaceous substances; high boiling hydrocarbons of aromaticcontent having olefinic and/or naphthenic content.

Starting materials of the present process also include tars of aromaticcontent from which low boiling fractions have been removed, as forinstance tars from which solvent oils have been removed Viewed broadly,the starting materials of the present process are tars of aromaticcontent, fractions of said tar more viscous than the starting materialdue to removal of W boiling fractions from the starting material, highboiling fractions and pitches. Starting material previously subjected tothe action of hydrogen are suitable.

Especially suitable as starting material is high Cil temperature cokeoven tar which is available in` Y large quantities at low prices.

The present invention may be viewed broadly as a process for theproduction of refined solvents of lowered corrosivity by subjecting thestarting material, in step-wise mannen'to the controlled action ofhydrogen whereby to produce solvents having. enhanced solvency, and ascompared to the intermediate parent material, an increment of fractionsin the low boiling range in excess of fractional increment in the higherboiling range,

, a specific gravity of in the order of 1.06, and

substantially 25% residue above 355 C., is subjected to the action ofhydrogen at 385 C. and

200 atmospheres pressure whereby to lower sulfur content, therebylowering corrosivity, at least providing for lowered corrosivity in thefinished material as hereinafter explained. The creosote of loweredsulfur content is then passed in liquid phase through a high pressurereaction vessel while simultaneously iiowing hydrogen therewith in thepresence of a molybdenum oxide catalyst at a temperature of 400 C. and350 atmospheres pressure. The time of contact is one hour 'and the flowof gas 15,000 cubic feet per barrel refined creosote. The beneciatedcreosote upon inspection Will be found to have a lowered boiling range,specific gravity, coke residue and viscosity. Solvency in some of thelower fractions of the' beneciated creosote will be reduced as comparedto solvents extant of comparable boiling range.

The beneciated creosote is stripped to an up-` per limit of 300 C. andthe distillate is passed through a high pressure reactor at 455 C. and200 atmospheres pressure while contacting a molybdenum oxide catalyst.The flow of hydrogen in coordination with other process variables is socontrolled as to induce a solvent having increased solvency and anincrement of fractions' in the lower boiling range in excess offractionalincrement/ lof fraction in the higher boiling range.-

The solvent so produced may be fractionated to provide rened solvents oflowered corrosivity of any boiling range within the limits of theimmediate parent material, as for instance:

Degrees centigrade Benzol 78-120 Toluol -150 Hi-lash naphtha -200 Heavynaphtha 150-290 Plasticizers -360 or others.

The rened solvents of lowered corrosivity may serve as substitutes forthe commercial solvents noted.

In the foregoing example it will be noted that the present processprovides a method for contacting the starting material with hydrogenwhereby to lower sulfur content, thereafter, contacting the material oflowered sulfur content with hydrogen in the presence of an oxidekcatalyst whereby to produce an intermediate product of loweredsolvency, specific gravity, boiling range, coke residue and viscosity;stripping from the beneciated material a low boiling fraction thereofand subjecting at least a portion of low boiling ends to the controlledaction of hydrogen whereby to enhance solvehCy, and produce as comparedto the immediate starting material, an

increment of fractions in the lower boiling rance in excess offractional increment in the higher boiling range, thus providing therefined solvent of lowered corrosivity of the present invention.

Looked at in one manner, the present process provides a method fortreating tars of aromatic content, and fractions thereof, with hydrogenin step-wise manner whereby to produce refined Solvents of loweredcorrosivity, said solvents beine characterized by increased solvency ascompared to their immediate starting material as heretofore disclosed.The step-wise action of hydrogen is characterized rst by providinghydrogen in levv that depolymerizes ring multiplicities thereby inducinglowered specific gravity, coke residue, boiling range, solvency andviscosity, and last, by providing hydrogen in flow that, among otherthings, increases solvency.

The aforenamed step-Wise action of hydrogen thus provides a method forsecuring refined solvents of lowered corrosivity from heavy or highboiling hydrocarbons of aromatic content, said high boilerscharacterized by the presence of ring multiplicities of great thermalsusceptibility.

Example HA sulfur containing coal tar, specic gravity 1.1641, a cokeresidue in excess of 5%, and in excess of 35% boiling at 355 C. issubjected to the action of hydrogen at 380 C. and 200 atmospherespressure for such a length of time as to lower sulfur content, the whileprecluding substantial induction of low boiling ends. The coal tar oflowered sulfur content is then passed in liquid phase through a highpressure reaction chamber while simultaneously flowing therewithhydrogen at a pressure of 300 atmospheres and a temperature of 410 C.;time of contact is one hour, catalyst vanadium oxide, and ilow ofhydrogen 15,000 cubic feet per barrel feed stock. The thus treated coaltar is found to have a lowered specific gravity, viscosity, and cokeresidue. In some of the fractional parts of the treated coal tartherewill be lowered solvency as compared to solvents extant of comparableboiling range.

The beneficiated tar is then stripped to an upper limit of 360 C. andthe low ends thereof subjected to the action of a flow of hydrogen at4509 C. and 200 atmospheres pressure for such a length of time as toincrease solvency and produce an increment of fractions, as compared tothe immediate starting material, in the lower boiling range in excess offractional increment in the higher boiling range, thus providing therefined solvent of the present process.

Example 3.A high boiling coal tar fraction of sulfur content, initialboiling D Oint of substantially 245 C. is subjected to the action of hy`drogen at 375 C. and 250 atmospheres pressure for such a length of timeas to reduce sulfur content. 'Ihe coal tar of reduced sulfur content isthen passed in liquid phase through a high pressure reactionchamberwhile simultaneously flewing hydrogen therethrough at atemperature of 410 C. and 300 atmospheres pressure; the catalyst ismolybdenum oxide and flow of hydrogen so controlled as to induce nosubstantial percentage of coke in the reaction chamber, nor percentageof chain structures as to preclude final solvent production as stated.

- Upon inspection the beneilciated coal tar frection will be found tohave a lowered specific grav- Y, ity, coke residue, boiling range andviscosity, and,

in the case of some fractional parts of the beneficiated material alowered solvency as compared to solvents extant.

The beneciated material is stripped at 290 C. and the distillatesubjected to the action of hydrogen at 450 C. and 200 atmospherespressure, flow of hydrogen 5,000 cubic feet per barrel feed and the timeso controlled as to providean increment of low boiling fractionsinexcess of fractional increment in the higher boiling range. Thesolvency of the finally processed material is in excess of the solvencyof the immediate starting material. `The time in the last step may be afractional part of a minute or more.

The residue incidental to the stripping steps may be recycled or used asan article of commerce of enhanced value, as for instance binders,plasticizers or the like.

The starting material of high carbon content, as for instance coke oventar is characterized by. in its raw state, such a percentage or highmo1eeular complexes or polymerized products that the refined solvents ofthe present invention are not possible of manufacture therefromdirectly, but must be produced in step-wise manner, as heretoforeexplained, whereby among other things, the action of hydrogendepolymerizes said molecular complexes contained in the startingmaterial.

The depolymerized or partially depolymerized tar or fractions thereof oflowered sulfur content is then stripped of a percentage of its low endswhereby to provide the intermediate parent material of the refinedsolvents of lowered corrosivity, said rened solvents beingAcharacterized, as compared to the immediate starting material, by anincrement of fractions in the lower boiling range in excess offractional increment in the higher boiling range; the residue incidentalto said stripping may, because of its depolymerized or partiallydepolymerized condition serve as recycle material to the end thatconversion of the starting material in the percentage nally remainingliquid approaches volume for volume of the starting material into therefined solvents of the present invention.

In the conversion of starting material, partially or approaching unity,into the refined solvents of lowered corrosivity, temperatures as low as300 C. may be employed; pressures as low as 50 atmospheres may be used.However, temperatures and pressures of an increased range provide bettercommercial practice. The time element is desirably that period whichaffords commercial recoveries of the products 0f, and incidental to, thepresent invention. Temperatures are preferred that cause no substantialamount of coking.

Gas flows are usually held in excess of 2,000 cubic feet per barrel feedtreated. In the stepwise application of hydrogen a few trials when usingany of the starting materials will determine the gas flow whencoordinated. with' the selected temperature and pressure conditionstoeffect said depolymerization.'v The gas flow in this instance may 'be avariable quantity because of the varying ranges of coordinatedtemperature and pressure that may be selected.

i Concerning the gas iioW that' increases solvency and provides anincrement of low boiling fractions in excess of fractional increment inthe higher boiling range, said gas flow is held at that point whichinduces no percentage of final liquid chain structures that wouldpreclude the enhanced solvents of the present invention; For a givencoordination of temperature and pressure, the gas ow in the lastinstance is lower than the gas ow in the preceding instance.

Using some starting materials a gas flow of 10,000-15,000 cubic feet perbarrel feed, or higher, has proven satisfactory for depolymerizingconditions, and, gas flows of in the order of 6,000- 8,000 or lower whenincreasing solvency have proven satisfactory.

Viewed broadly the hydrogen flow in the instance of obtainingdepolymerizing conditions may be lower than 10,000 cubic feet per barrelfeed, and the flow in the last instance is held at that point thatincreases solvency.

In the hydrogen action that reduces sulfur content, the action ofhydrogen may be effected in an intermittent autoclave or in a continuousplant, and in the event of continuous practice, the gas flow ismaintained so as to assist in sulfur reduction and the removal thereoffrom the reaction zone, the while inducing no substantial percentage ofcarbon, low boiling fractions or percentages of liquid chain structuresthat would preclude the provision of the refined solvents of superiorsolvency of the present process,

By the term beneflcated as used herein and in the appended claim ismeant the starting material at least once subjected to the action ofhydrogen in accordance with the present process.

After the starting tar has been subjected to depolymerizing action, thestripping step may be effected at any point selected within a Wide rangeto provide a cut capable of providing, after fur.- ther processing,substitutes for the boiling ranges of benzol, toluol, xylol, the variousnaphthas and the various plasticizers.

Thus, the depolymerized starting material may be cut according to theneed at hand, said out then being subjected to the action of hydrogenthat increases solvency as heretofore explained.

The catalysts of the present invention are oxides; as for instanceoxides of metals of the 6th and 8th periodic groups; the oxides of othergroups may be used, howevery dicultly reducible oxides are preferred.The catalyst in any form may be employed, as for instance pellets,comminuted, supported on carriers or the like; in any effective form.

If desired, comminuted catalyst may be used in the hydrogen stepcharacterized by depolymerization, and in the step characterized bysolvency increase, a rigid catalyst may be used.

By multiplicity of rings, high molecular complexes and polymerizedproducts are meant high boiling fractions of aromatic content, a portionof which at least may be viewed as ring multiples; or, said terms, anyor all, may be used to describe high boiling fractions of the startingmaterial'which because of high carbon content are especially susceptibleto thermal degradation.

When subjecting high boiling fractions of the starting material to theprocess of the present 1nvention,'it may be desirable Yprior tothedepolymerizing step, or the sulfur reduction step, to at least partiallydepolymerize the molecular complexes by use of a solvent. Said solventmay be added in a small amount, or up to volume for volume or more.Refractory solvents are desirable, but others more susceptible to thereactions inherent' inv and to the present process are usable. T

Concerning solvents, it may be said that tar Y in itself, as forinstance coke oven tar, is constituted of high molecular complexesdissolved, cut back or depolymerized with a solvent, said solvent beingthe lower boiling fractions of said tar.l

' The action of hydrogen may be effected inone or more cyclesor in oneor several chambers, with or without releasing the pressure, and with orwithout variation of process controls.

Various modes of practicing the present invention are possible, as forinstance, the depolymerized starting material may be stripped as forinstance by gas movement; the low ends thus stripped may then, with orWithout releasing pressure, be subjected to the further action ofhydrogen. Or, the desired stripped material may be obtained by partialrelease of pressure which would correspond to the fractional recoverydesired or predetermined.

The process may be practiced in an autoclave and/or a single reactionchamber, a series thereof, a parallelism thereof including amultiplicity thereof.

The refined solvent of the present invention may be fractionated toprovide solvents and/or plasticizers of various boiling ranges, and inthe instance where solvents are processed from a. deep cut on thedepolymerized material, the highest boiling fraction thereof or others,may serve as a substitute for certain plasticizers.

In the first cycle of hydrogen action that reduces sulfur content, saidreduction of sulfur may be accomplished in the presence of a catalyst.Catalysts effective in the presence of hydrogen are usable, as forinstance the oxides and/or sulfides of molybdenum, vanadium, uranium,cobalt, tin, manganese, tungsten, or the like.

In the disclosures herein made the removing of low boiling fractions bygas movement or pressure release is considered the equivalent ofdistillation.

When reference is made to high molecular complexes contained in thestarting material, and when the starting material contains low boilingfractions that are not considered high molecular complexes, it is ofcourse obvious that the high molecular complexes contained in thestarting material are to a certain extent depolymerized by the solventpresent.

It will be seen that by reduction of sulfur content of the materialunder treatment during any stage of hydrogen action, the oxide catalystused during subsequent stages is at least partially protected from theeffect of the sulfur.

The term pitch as used herein includes the higher boiling fractions oftar, in other Words tar from which low boiling ends have been removed,such low boiling ends being suitable per se as creosote, other woodpreservative, or solvent. For instance the nal residue resulting fromevaporating tar to dryness or substantial dryness (coke or hard pitch)and then stripping Wood preservative from the distillate is a verysuitable pitch for use as a starting material of the .present process.Minor changes may be made within the scop of the appended claim withoutdeparting from the vspirit of the invention.

I claim: l In the production of solvents from a mixture ofsulfur-bearing high temperature coil tar fractions, the process whichcomprises: subjecting said tar fractions to the action of hydrogen, withtime, temperature and pressure so controlled as to reduce sulfurcontent; subjecting said tar fractions of lowered sulfur content to theaction of a relatively high ow of hydrogen whilst contacting ascatalytic material an oxide of a metal, said hydrogen ow being selectedfrom the range fractions in the lower boiling range in excess offractional increment in the higher boiling range by subjecting saidstripped low boiling material to the action of a relatively low flow ofhydrogen, a temperature and pressure of at least 300 C. and 50atmospheres, respectively, to produce a solvent.

JACQUELIN E. HARVEY, J n.

1 CERTIFICATE 0E CORRECTION. Patent No. 2,519,990. May 25, 19.1.5.

JACQUELIN E. HARVEY, JR.

It is hereby certified that error appears in the printed specificationof the above nmbered patent requiring correction as follows; Page l,first column, line 56, .after the word "removed" insert aperiod; secondcolumn, line 51T, for "50o c." read --5000 0.--, line lia, for"fraction" read --fractons--g page 5, second column, line l1, strike out"in"^; and that the said Letters -Patent should be read with thiscorrection therein that the same may conform to the record of the casein the Patent Office. v

Signedand sealed-this 6th day of July, A. D. 1914.5.

` Henrr Van Arsdale, (Seal) Acting Commissioner of Patents.

